CD22 is a B lymphocyte specific glycan binding protein that participates in regulation of B cell receptor signaling. The extra-cellular domain recognizes sialic acid containing glycans as ligands that regulate its activity during B cell activation and differentiation. Because it is specifically expressed on B cells, CD22 is also a clinical target for antibody based cell depletion therapies for treatment of B cell lymphoma and inflammatory autoimmune disease. We have developed an approach for targeting B cells using multivalent glycan ligands of CD22. In this project we will develop B cell targeted liposomes using glycan ligands of CD22, and test their utility for depletion of B cells in murine models of disease. The major objectives of the project are: 1) Develop chemotherapeutic loaded liposomes displaying ligands of human CD22 that efficiently and specifically target and kill B cells. 2) Assess the in vivo efficacy of CD22 targeted liposome formulations in a murine model of human B cell lymphoma. 3) Test the ability of CD22 targeted liposomes to bind to cancer cells in the blood of human B cell leukemia and non-Hodgkin's B cell lymphoma patients. 4) Determine if B cell depletion with CD22 targeted chemotherapeutic liposomes exhibit efficacy in a murine model of autoimmune disease. If successful, the results may lead to the development of cell-targeted therapies for treatment of B cell malignancies and inflammatory autoimmune diseases mediated by B cells. PUBLIC HEALTH RELEVANCE: Many non-Hodgkin lymphomas and leukemias are derived from B lymphocytes. B lymphocytes are also increasingly recognized for their key roles in many autoimmune diseases such as rheumatoid arthritis. B cell depletion therapies have been demonstrated to provide significant clinical benefits in these diseases. Improvements in these approaches are likely to provide increased efficacy and stimulate their expanded uses to the benefit of patients with B cell malignancies and chronic inflammatory diseases. Our project is aimed at the development of novel methods of targeted B cell depletion therapy to meet these needs.